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Dielectrophoresis assisted concentration of micro-particles and their rapid quantitation based on optical means

Ghubade, Anil and Mandal, Swarnasri and Chaudhury, Rahul and Singh, Rajeev Kumar and Bhattacharya, Shantanu (2009) Dielectrophoresis assisted concentration of micro-particles and their rapid quantitation based on optical means. Biomedical Microdevices, 11 (5). pp. 987-995.

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Abstract

Abstract The detection and counting of micro particles having sizes comparable to biological entities can provide a tremendous impetus to rapid diagnostics and clinical applications. MEMS technology has already been used in capture and detection of such micron size entities in miniscule concentrations. For this purpose a concentration step is normally added prior to the detection process. A variety of methodologies are used for quantization of such micron size particles/entities including change in permittiv-ity, medium impedance, magnetic permeability and other means. Although optical studies have been extensively performed prior to this, it has not been used for quantization of the micro particles. We have designed, developed and characterized a MEMS counter which captures micron size fluorescent beads using delectrophoresis (DEP) and mon- itors their accumulation in a 12 μm×230 μm size channel and monitors this accumulation as growth of overall fluorescence. The field is generated by a set of finely placed interdigitated microelectrodes. As we apply an alternating voltage at 10 Vpp for a range of different frequencies we are able to capture the flowing beads and concentrate them by several orders of magnitude. This is also followed by their quantification in terms of growing fluorescence signal. For quantitating the fluorescence values a CCD (charge couple device) module fitted over an inverted fluorescence microscope is used that visualizes the whole capture process and a Labview based image acquisition software simultaneously calculates the signal intensity over these frames and arranges it temporally. Ourwork will have tremendous utility in developing a rapid bacterial counting procedure and will be a valuable tool in microbiological laboratories.

Item Type:Article
Subjects:Biomedical Science > Nanobiotechnology
ID Code:7993
Deposited By:CSMNT
Deposited On:26 Aug 2010 09:18
Last Modified:26 Aug 2010 09:18

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